Breath Volatile Organic Compounds Across the Menstrual Cycle: A Pilot Study Using PTR-TOF-MS
C Eckhardt1, W Lederer1, L Wildt2
1Department of Anesthesiology and Critical Care Medicine, Medical University of Innsbruck, Anichstr. 35, 6020, Innsbruck, Austria.
Background:
Accurate identification of ovulation remains challenging due to pronounced inter- and intra-individual variability of reproductive hormones. Volatile organic compounds (VOCs) in exhaled breath may vary across the menstrual cycle and offer a non-invasive complementary approach to menstrual cycle assessment.
Methods:
In this pilot study, exhaled breath VOCs were measured using proton transfer reaction time-of-flight mass spectrometry in five healthy women across follicular, ovulatory, and luteal phases of a natural menstrual cycle. The VOC profiles were compared between ovulatory and non-ovulatory measurements, and correlations with serum hormone concentrations of estradiol (E2), luteinizing hormone (LH), and progesterone (P) were explored.
Results:
A significant difference between ovulatory and non-ovulatory measurements was observed for the ion m/z 41.04 (p = 0.021). Non-significant trends toward higher concentrations during ovulation were detected for isoprene-related signals.
Conclusion:
Breath VOCs exhibit phase-dependent alterations across the menstrual cycle. The observed increase in the m/z 41.04 signal during ovulation may reflect integrated metabolic adaptations associated with endocrine changes rather than direct surrogates of circulating hormone concentrations.
